The objective of this proposal is to continue a program of research designed to determine the course of development of visuospatial functions in human infants and children. The results will be relevant to our understanding of maturational and exposure-induced changes in the underlying neuronal mechanisms, to the recognition of early, potentially pathological, deviations from normal developments, and to possible ameliorative treatment. The following six specific directions of research are proposed. 1. Development of Orientational Selectivity: To determine the course of the sharpening of orientational tuning to edges through infancy and childhood. 2. Development of Spatial Frequency Selectivity: To determine the course of progressively narrowing tuning during infancy and childhood. 3. Development of Binocular Vision and Oculomotor Control: To establish the relationship between the development of stereopsis, the directional symmetrization of monocular OKN, and eye alignments to visual targets. 4. Analysis of Early-Onset Myopia and Visual Function in Children with Known Refractive Histories: To determine the influence of infantile refractive error on later error and on visual and oculomotor function. 5. Analysis of Sex Differences in Visual Development: To determine the magnitude and time course of sex differences and their hormonal cause. 6. Computerized Data Base and Control of Testing Procedures: To continue cumulating data under computer control and developing automated test procedures for use in laboratory and clinic.